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sion ci such av system in which NET@ @Tg5 FATE@ FFE ALBEN E. LUNDEIQL, or NEWYORK, N. Y.. AssiGNoB-'ro WESTERN ELECTRIC COMPANY, INCORYCRATED, or NEW YORK, N. Y., A coneoRA'rIoN oFNEw YORK.

Specilcation o'if'Lettcr Patent.

remitted Auw-15,1916.

Application filed January-14, 1916. Serial No. 72,148.

To all 'whom it may concern:

Beit known that I, ALnrN -ll LUNDI-:m5, a. citizen df the LUnited..Stute',,residing at New York., in the C' 'Bronx and State of Newf Yorl'gf l Vented certain new and useful lrn'prexfe nts-in Automatic Telephone Systems, chg-the following is :r full, clear, ccncise, and exact description.

This inventiod'relates to telephone systenis in which automatic or electrically cperated switchesa-re employed in establishing connections from calling to called lines.

The obiect of the invention the 1; o vi.- r-hc 'sv-1 itclr ing devices are controlled. entirely crea. single non tallring conductor. and more 'p :ir-` ticulztrlyv to a, system of this type-in which controlling xnagnetsoperating on close mairg'ms will be avoided. v

The switches einployedjilr the present in-A structu group of contacts und, magnet and vfre the set of magnets in th l. l the control Gita-seco `d of thisl general chara'eterf to Keith etal -N.8 ,71R The accompanying'sl grumrnatically indicate circuits employed 'inf Y ment of this' invention.L

T he side switch employed may be simi ar in character t0 the one'discloscd 'in said Keith patent, 'but isl arranged tQ-nin're its wipers in certain instanc-cs'upon the energi-1 zzition instead of upon'the denergiz/.iition of its actuating magnetT crating inthis manner is Clisclosedin un application 0.1iv Oscar Forsberg Serial No. (530i), filed Februfry 5, 1915. The side suih. herein disclosed ismoved from posr Linn 'i to position Z upen'thcrst encrgizu- 'A side Switch ogltion mi .its controlling or escape muguet,

from position i2 to positif-n 3 upon the ond rlcenergization (if its ape muguet.F

:uni from-position 3 Ljo position ai -upnn 'the nest energimtion of ese-ipe magnet.

The culling device indicated at the substrii'inn the subscriber@ line muy he of any Nl character in which a snif of' infieA prod-r. l in potential.

ot' this character is disclosed in upplicunts lutent No. 1,148,912.

lt is believed that 'the intention will nonbe readily understood from the (lescriptinu ef the. manner in. which the switches `:irc

controlled in establishing n connection.

In the drawings, l and?, represex'ltcounecting circuit terminals which are brought into association with the terminal contucts of the cullingl line in any desired manner.A

3 und l representnornnillyopcn contacts in the selected connecting circuit which are. Cinsed immediately fclloiring the association of the connecting circuit 'with the culling;

line. l

- is the impulse relay by means- 0fwhich the uctlvmtiug.impulses `are transmitted to the stepping magnets of. the switcl'les.-

If the present invention-'ris employed in Va semiautomaticfinstea'd of affull automatic system, the steppingA relay 5 will ope ,ztat'ec l` by the central -operiltorssending device instead of hy impulses `trzjtns'initted from `brushes 9. 1U and' il: Relay 5 Will be enen. gized closing' a circuit frozn battery through the Contact 'and :furniture of i n1pi.1lse reluy 5. Winer 13 :intl the right; wirnlinc' of the. i

escape magnet 14 :it the first selector switch l I v t0 ground. lllngnet ll. is cnergizei'l il mores the. side. switch \-'xpers fronrp( )tu i to position 2. in moving ,to nos' lxoi 'a through relay l5, wiper and tl. :innuture :1nd Contact of relay' l5 itil" 'grmuil through thc 2l 'mit lmltery. v-lll l5 will attract its armature. thus contini-fing :l circuit for the slow release relVilG.

The callingY su`nsr.\ilw.r 4 ill"no \v operate his dial m canse :i series i the substation circuiti lll-lili czicixi1`iterriiption o said. circuit, relai/' Vwill retract its in l' l ll G ,winding of the escape magnet opening the circuit for relay 15, which will in turn retract its armature. Relay 16 being slow to release remains up throughout the series of impulses. With each denergization of relay 15, a circuit is completed from the 48 volt battery through the primary steppingr.magnet 17 and the escape relay ,18 in parallel, and thence through the front Contact and armature of relay 16 and the back contact and armature of relay 15 to ground. Magnet 17 and relay 18 will b oth be energized, and relay 18 vwill close a circuit from battery through the, left Y 14, armature and Contact of relay 18, Wiper 19 and the right winding of magnet 14 back to battery, thus energizing the escape magnet. The Side switch, however, will not be operated this time until the escape magnet is denergized. Relay v18 being slew to release is held up during the series of impulses. Magnet 17 rapidly attracts and retract; its armature, moving the brushes 9, 10 and 11 of the selector switch from group to group of the trunk terminals.

Upon the termination of the series of inipulses, relay 5 will remain energized, and will hold the circuit for relay 15 closed. Relay 18 will then retract its armature, opening the circuit for the escapemagnet 14 and causing the side switch to move to posi tion 3. As` the side switch moves to position 3 the circuit for relay 15 is interrupted, and it retractsits armature, but a substitute armature,

lcircuit is completed for the holding relay 16 through the side switch wiper 18 in position 3,-thus preventing'the release of the switch. I

The escape magnet 14 is employed as a. test relay. In position 3 of the side switch, a circuit is closed from the 24 volt battery through resistance 9.0, wiper 19 and the right winding of relay 14 to ground. The current flowingr over this circuit, is, however, insuflicient to cause magnet 14 to pull up its armature. At this time a. circuit is closed from battery through the left winding of magnet 14 and wiper 21 to the test brush 19 of the selector switch. The test or guarding contacts of trunks leading to idle second selector switches will ber connected to ground through a side switch wiper as 13 at the second selector and the left winding that switch. Il", however, to such switch is busy, contact will be provided tial. This may be supplied in several different manners, depending on the stage of operation of the switch which has selected the connecting circuit, and of the switch at which the circuit terminates. 1f the connectingfcircuit has just been selected at one of its multiples and the side switch of this connecting circuit has moved to position 2,

a trunk leading its test or guarding with battery potenof the escape magnet 14 of' it is obvious that the test conta-cts will be connected to the 48 volt battery through wiper 13 and stepping relay 15. At this time, however, the 24 volt battery atthe impulse relay 5 will also be connected to said test contact by a circuit extending through wipers 13 and 21, in position 4. Therefore, the potential of the test Contact will be of substantially 24 volts, and current will there fore not flow through the lett. winding of magnet 14 in such a manner as to cause its energization. It' the calling subscriber connected to the connecting circuit is at this time transmitting impulses, the battery at the ixnpulse relay 5 will be removed from the multiple test contacts of the connect-ing circuit with each denergization of relay 5, leaving only the 48 volt. battery at relay 15 associated with said contacts. The flow of current, however, from this battery through the left Winding of magnet 14, is in a di.` rection to oppose the ilow of current through its right winding, and magnet 14 will not be energized. If the side switch Wiper of the s witch at which the connecting circuit terminates is in position 3 or position 4, the saine condition will exist, except that the test contact will be connected to the 48 volt battery through relay 16 instead of through relay 15. If the switch associated with a multiple of the connecting circuit is just in the process of testing and the side switch has not yet: moved to position 4, the second switch to arrive on the multiple test contact will find batteryY potential thereon and its test, relay or magnet 14 will not be energized.

When the second selector side switch was moved to position 3, a ci rcuit was etsablislied from battery through the secondary stepping magnet 22, wiper 23 and interrupter 24 to ground. `This circuit will be main` tained and the brushes 9, 10 and 11 will be stepped from trunk to trunk until the contacts o an idle .trunk are engaged, when current will flow through the left winding of magnet 14 in a direction to assist the current flowing through its right winding, thus energizing the escape magnet and moving the side switch to position 4.

It is obvious from the preceding description in what manner succeeding selecto-r switches would be operated. The secondary magnet of the connector switch mig'it be arranged toghe substituted by a side switch wiper for the primary magnet in the circuit controlled by relay 15. It is believed this is obvious and will not require further description.

In the present embodiment ol the invention` the release of thc switches is controlled solely by the calling subscriber in replacing his rcceii'er upon its hook. When this occurs the holding relays 16 of all of the switches will be deprived of current and will release their armatures, causing the ree.' l'- izo tials in the prese-nt invention, thenecessityYV for controlling relavsopcrating on narrow margins has been avoided, thus making .it

possible to pri-idrico a practical telephone srs-tem in which the automatic switches are lil rontrolledsolcly over a single non-talking conductor. i v

l.. in a. telephone s) 'tic-ni, an electrically operated switch, aconduct-or extending to said switch, Va guarding Contact for said swit-cli connected 'to-said conductor, a source of current, means for joining said source to said conductor', ay controlling magnet for said switch, means for joining said magnet to said conductor, and a second source of current. of different potential :from said first nuaitioncd source in scrics with said controlling magnet. y

ln a telephone system, an elcctricalli.v oilierated switclna conductor extendingto .said switch, a. guarding 'Contact for said switch connected to said conductor, a hat'- tery, an impulse relay for joining;Y said battery to said comluctm'` asteppinzgIr magnet. for said Switch.y means for joining said magy not to said conductor, and n. secondhattery of different potential from the first mentioneil battery inA with'said stepping" magnet, 'whcreh` battery potential is continuously.appliid to said guarding cont-act.

.ln a telci'ih'onc system, an electrically oi'icratcd switch, a connecting circuit extending: to said switch, a guardingr contact for :said ronnecti:rgT circuit in one of the (rondini-ors 0i" A' reni.T moans 'for connoct-ing!I said source to said conductor, a controllin;Y magnet for .said L .ti-h, means for joining;r said magnet to .t id cond'u r, and a second source (if cuiicnt of different'l'iotontial from said first n'ifntioncd source in series with .said magnet.

4. 'ln a telephomV` system, an clcctricalljif opera'tcd switch, a conductor extcnding .to said switch. n'niltipli-Y conncctcd guarding contacts for said switch, one oi' said contacts being in said conductor` a. source ofcurrent, means for joining said source to said conduetor, a stepping magnet. for said switch, ineans for ioining` said i'nagnet kto said conductor. and a. sceond- .source oi" current of gre-atm' potrnt-ial than Said first nieutioucd soin-co in series with said controlling;r `magnet.

ln Va telephone system, an electrically oi'iviiited switch. a conductor oxtendingj to* sind, switch, xniiltipllr 'connected guarding' 'the test contacts of 'said mrc d circuit, a.. source of eurcontacts for .said switch, one of said contacts being` in sai'd conductor, an impulse rela),r for joining" said battery to said conductor, a stepping magnet. for said` switch, mea-ns for joining;` said magnet to said Conductor, and a. second hati'fc 'y of dilfercnt p0- tcntial from the. firstnientioncd battery in serios with said stopping" magnet, vwhereby batteryA potential is continnouslj,y applied to said guarding cnntacts.

G. In a 'telephone system, connecting circuits, multiplo test contacts orsaid circuits respectively, means for connecting the, Vtest contacts of busy circnitswith asource (rtf current, a switch` a brush for said'switcl.,

- means for moving said switch to cause said brush lo traverse the test Contacts of' said A`circuits, a test magnet for said switch, a

pair of windings onsaid magnet, means-to provide a flow of current.' througlr one of said windings` which is insufficient to opcratc said magnet, and a circuit orsaid other winding, includingr said brush and said con tacts sncccssi: the flow of currentthrough the second winding, from the test contacts of busy circuits, being in :i direction to oppose the flow through said first mentioned winding.

7. ln a telephone system, connecting circuits', multiple tlc-st contacts for saidcircuits respectively.' means for supplying .Said tesi'y contacts with varying potential according :is said circuits are busy or idlo, a. switch, a test brush on i Said switch to canse l4 v'liruh ,to traverse its@ tiest magnet forsaid switch, apair of kindings on said mag'nctt means to proridea flow of current through one of said wiralings 'a'circnit 'for said other winding includinf" vaid test brush andv said contacts successively, the flow of current through tho second winding from the test contacts of busy circuits being in a, Vdircetion to oppose theflow through the first. mentioned winding, and the flow of current through .said sccond winding being in a direction to assict said first mentioned wind in; when thc Contact of an idle circuit. is cnringed.

S. In a telephone system, connecting cirvisl dswiteh, means formoving cuits, multiple tcst contacts 'for said circuit-s respectively, 'means for supplying the tcst contacts of busy circuitsiwith busy potential, a switch, a. testbrush on said` switch` means for moving switch to cauA said brnshito traverse t it contacts of salu circuits` va test magnet foi-said switch: a pail of windii gs on said*magnet,inciins to pro'l ride a flow .of 'current through one of `mid windings which is insufficient to opi-rail(- .said

'niagnch a circuit for said othcr \.\'iniling in Vcluduag saul test. llrushgand said contara successiveli', the flow -of furront. through thc v5er-.ond Ywinding' from thc tosi con arts ol' busy' circuits liciug in a dircctiffn io opposc the-'How through the first mentioned winding, and the flow of current through said `second winding being in a direction to assist the first mentioned winding when the contact of an idle circuitis engaged. i

9. In a telephone system, connecting circuits, multiple test contacts for said circuits respectively, ymeans forrsupplying the test contacts of busy circuits with busy potential, va switch, a brush on said switch, a stepping magnet for moving-said switch to cause said brush to traversetest contacts of saidcircuits, a side switch, a circuit for said steppingmagnet including a. wiper of said side switch, an l.operating magnet for said` side switch, a pair of windings on'said operating magnet, means to provide a flow of current through one of said, wlndings which is insuficient to operate said magnet, and af circuit for ysaid other winding including said test brush and said contacts succes 'sivcly, the o'w of current through the secl ond winding from the test contacts of busy AEl() ping magnet for moving said switch to causev circuits being in a direction to oppose the flow through the first' mentioned winding.

10. In a telephone system, connecting circuits, multiple test contacts for said circuits respectively, means for supplying the test contacts of busy' circuits with busy potential, av switch, a brush on said switch, a stepsaid brush to traverse test contactsof said clrcuits, a. side switch, a. circuit for said .stepping magnet including awiper of said side switch, an operating magnet for said side switch, a pair of windings on said operating magnet, means to provide a flow of current throughone of said windings which winding when the contact of an idle circuit is engaged. y

'11i Ina telephone system, an electrically operated switch, a circuit extending to 'said switch, multiply connected guarding con tacts for said connecting circuit, one of said contacts beingin vone of the conductors ,of said circuit, .a source of current, un impulse relay for connectingl said source to said conductor,.a controlling 'magnet -for said switch,

means for joining said'magnet to -said conductor, a second source of current of different potential from said first mentioned source in series with said magnet, a second switch having a brush arranged to engage for said second switch, a pair of windings on said magnet, means to provide a flow of current through one of said 'windings which is insutiicient to operate said magnet, and a circuit for said other winding including said brush and said multiple guarding'contact, `the flow of current through said second winding being in a direction tooppose the Yflow. through the first winding.

In witness whereof, I hereunto subscribe .my namethis 13th day of January, A. D.

1 ALBEN E. LUNDELL.

one of said multiple contacts, a test magnet 

